For what it's worth, most US dealers have the Bose's in at $995 or so. Probably will have to add State sales tax to that, which could be 6% or more, depending on where it's bought. Then they have to be shipped, and you 'll pay VAT and a bit of duty.
About £740 here including VAT from Headset Services and others.
I'd rather have the peace of mind of solid backup here, and the protection of the Sale of Goods Act. Bose headsets are great (spectacles are not a problem), but they are more delicate than DCs. They are lighter than competitive products and the ANR is amazing.
If you are prepared to buy Bose, in the overall scheme of "things flying", I reckon it's worth the extra few pounds you may pay here. Remember, it's just possible that you won't like them (improbable), and would want to return them after a few days to exchange them for something else - a bit difficult if they were acquired by somebody else on the other side of the Pond. I know you tried them at a dealer, but you need to try them in a PLANE.
Regards.